I came across these on a recent search for diving masks. Without further investigation (I’m not in this to work) I attempted to depict a possible function for the dongles seen on top of the helmets. At left, I imagine they serve as emergency flotation devices. Anyone with more knowledge of these diving helmets should feel free to clarify.
EARL OF TAINT 
whatever it does, it appears she is enjoying it….
That doesn’t look anything like the helmet Diver Dan wore…
Can’t help you on this one, Earl…….most of my diving experiences have been “muff” diving.
Good afternoon Mr. Taint.
Lingerie, Lubes, Liquor, and Eveningwear.
Going
Down!
Best guess it’s a handle for putting on and taking off. Designer with a sense of humor.